Best investment was a kid activity table from pottery barn. Looks like the current one there has a lip, but ours is flat. Takes a beating and still looks good. Several people didn't even realize it was an activity table. We have the drawers underneath and optional paper roll. We bought the extendable legs thinking we'd move it somewhere else as a study table/desk but we all love it in the family room. When kids are older we will detach the paper roll. We don't have a playroom or basement so this has been great for us.
we happened to get two of these right after our DD was born. They have been ideal - we can move around the room, she loves the tray part and it's soft leather. I know it's not technically a coffee table though.
We bought an inexpensive large storage ottoman from IKEA with removable/washable covers. In the evenings, you can stick a tray on top so you can put glassware on it; otherwise we keep it bare during the day when our toddler is gallivanting about.
My daughter is about to start crawling and we need to get a kid friendly coffee table. What do you folks recommend in terms of safety? Round/square, material, etc?